I'm sorry but I don't really understand the question. What is the quest actually asking???
Answer:
The leverage or mechanical advantage of pulleys is less obvious, but you can "gang" multiple pulleys together into two sets (blocks) and run the ropes back and forth between the two sets to increase the number of lengths of rope running between them. One end of the rope is connected (fixed) to one of the blocks, and you get to pull on the other end after it is passed back and forth between the blocks of pulleys. This is sometimes called a block and tackle arrangement. With a hook on each side of the block set, you can move a heavy load much like levers do, by multiplying the force. You have to pull more rope just like you have to move a lever more on one side of the fulcrum as compared to the other. When you get all the rope pulled out that you can, you can not move the load anymore because you have become "two-blocked" which means the two blocks are together. Credits to: Moin Khan
Given Information:
Resistance of circular loop = R = 0.235 Ω
Radius of circular loop = r = 0.241 m
Number of turns = n = 10
Voltage = V = 13.1 V
Required Information:
Magnetic field = B = ?
Answer:
Magnetic field = 0.00145 T
Explanation:
In a circular loop of wire with n number of turns and radius r and carrying a current I induces a magnetic field B
B = μ₀nI/2r
Where μ₀= 4πx10⁻⁷ is the permeability of free space and current in the loop is given by
I = V/R
I = 13.1/0.235
I = 55.74 A
B = 4πx10⁻⁷*10*55.74/2*0.241
B = 0.00145 T
Therefore, the magnetic field at the center of this circular loop is 0.00145 T
" .